aboutsummaryrefslogtreecommitdiffstats
path: root/fs/nfs/unlink.c
blob: 757415363422da022f2c7197779233d93b86e653 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
/*
 *  linux/fs/nfs/unlink.c
 *
 * nfs sillydelete handling
 *
 */

#include <linux/slab.h>
#include <linux/string.h>
#include <linux/dcache.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs_fs.h>
#include <linux/sched.h>
#include <linux/wait.h>

#include "internal.h"

struct nfs_unlinkdata {
	struct hlist_node list;
	struct nfs_removeargs args;
	struct nfs_removeres res;
	struct inode *dir;
	struct rpc_cred	*cred;
};

/**
 * nfs_free_unlinkdata - release data from a sillydelete operation.
 * @data: pointer to unlink structure.
 */
static void
nfs_free_unlinkdata(struct nfs_unlinkdata *data)
{
	iput(data->dir);
	put_rpccred(data->cred);
	kfree(data->args.name.name);
	kfree(data);
}

#define NAME_ALLOC_LEN(len)	((len+16) & ~15)
/**
 * nfs_copy_dname - copy dentry name to data structure
 * @dentry: pointer to dentry
 * @data: nfs_unlinkdata
 */
static int nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
{
	char		*str;
	int		len = dentry->d_name.len;

	str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
	if (!str)
		return -ENOMEM;
	data->args.name.len = len;
	data->args.name.name = str;
	return 0;
}

static void nfs_free_dname(struct nfs_unlinkdata *data)
{
	kfree(data->args.name.name);
	data->args.name.name = NULL;
	data->args.name.len = 0;
}

static void nfs_dec_sillycount(struct inode *dir)
{
	struct nfs_inode *nfsi = NFS_I(dir);
	if (atomic_dec_return(&nfsi->silly_count) == 1)
		wake_up(&nfsi->waitqueue);
}

/**
 * nfs_async_unlink_done - Sillydelete post-processing
 * @task: rpc_task of the sillydelete
 *
 * Do the directory attribute update.
 */
static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
{
	struct nfs_unlinkdata *data = calldata;
	struct inode *dir = data->dir;

	if (!NFS_PROTO(dir)->unlink_done(task, dir))
		rpc_restart_call(task);
}

/**
 * nfs_async_unlink_release - Release the sillydelete data.
 * @task: rpc_task of the sillydelete
 *
 * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
 * rpc_task would be freed too.
 */
static void nfs_async_unlink_release(void *calldata)
{
	struct nfs_unlinkdata	*data = calldata;

	nfs_dec_sillycount(data->dir);
	nfs_sb_deactive(NFS_SERVER(data->dir));
	nfs_free_unlinkdata(data);
}

static const struct rpc_call_ops nfs_unlink_ops = {
	.rpc_call_done = nfs_async_unlink_done,
	.rpc_release = nfs_async_unlink_release,
};

static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct nfs_unlinkdata *data)
{
	struct rpc_message msg = {
		.rpc_argp = &data->args,
		.rpc_resp = &data->res,
		.rpc_cred = data->cred,
	};
	struct rpc_task_setup task_setup_data = {
		.rpc_message = &msg,
		.callback_ops = &nfs_unlink_ops,
		.callback_data = data,
		.flags = RPC_TASK_ASYNC,
	};
	struct rpc_task *task;
	struct dentry *alias;

	alias = d_lookup(parent, &data->args.name);
	if (alias != NULL) {
		int ret = 0;

		/*
		 * Hey, we raced with lookup... See if we need to transfer
		 * the sillyrename information to the aliased dentry.
		 */
		nfs_free_dname(data);
		spin_lock(&alias->d_lock);
		if (alias->d_inode != NULL &&
		    !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
			alias->d_fsdata = data;
			alias->d_flags |= DCACHE_NFSFS_RENAMED;
			ret = 1;
		}
		spin_unlock(&alias->d_lock);
		nfs_dec_sillycount(dir);
		dput(alias);
		return ret;
	}
	data->dir = igrab(dir);
	if (!data->dir) {
		nfs_dec_sillycount(dir);
		return 0;
	}
	nfs_sb_active(NFS_SERVER(dir));
	data->args.fh = NFS_FH(dir);
	nfs_fattr_init(&data->res.dir_attr);

	NFS_PROTO(dir)->unlink_setup(&msg, dir);

	task_setup_data.rpc_client = NFS_CLIENT(dir);
	task = rpc_run_task(&task_setup_data);
	if (!IS_ERR(task))
		rpc_put_task(task);
	return 1;
}

static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
{
	struct dentry *parent;
	struct inode *dir;
	int ret = 0;


	parent = dget_parent(dentry);
	if (parent == NULL)
		goto out_free;
	dir = parent->d_inode;
	if (nfs_copy_dname(dentry, data) != 0)
		goto out_dput;
	/* Non-exclusive lock protects against concurrent lookup() calls */
	spin_lock(&dir->i_lock);
	if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) {
		/* Deferred delete */
		hlist_add_head(&data->list, &NFS_I(dir)->silly_list);
		spin_unlock(&dir->i_lock);
		ret = 1;
		goto out_dput;
	}
	spin_unlock(&dir->i_lock);
	ret = nfs_do_call_unlink(parent, dir, data);
out_dput:
	dput(parent);
out_free:
	return ret;
}

void nfs_block_sillyrename(struct dentry *dentry)
{
	struct nfs_inode *nfsi = NFS_I(dentry->d_inode);

	wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
}

void nfs_unblock_sillyrename(struct dentry *dentry)
{
	struct inode *dir = dentry->d_inode;
	struct nfs_inode *nfsi = NFS_I(dir);
	struct nfs_unlinkdata *data;

	atomic_inc(&nfsi->silly_count);
	spin_lock(&dir->i_lock);
	while (!hlist_empty(&nfsi->silly_list)) {
		if (!atomic_inc_not_zero(&nfsi->silly_count))
			break;
		data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list);
		hlist_del(&data->list);
		spin_unlock(&dir->i_lock);
		if (nfs_do_call_unlink(dentry, dir, data) == 0)
			nfs_free_unlinkdata(data);
		spin_lock(&dir->i_lock);
	}
	spin_unlock(&dir->i_lock);
}

/**
 * nfs_async_unlink - asynchronous unlinking of a file
 * @dir: parent directory of dentry
 * @dentry: dentry to unlink
 */
int
nfs_async_unlink(struct inode *dir, struct dentry *dentry)
{
	struct nfs_unlinkdata *data;
	int status = -ENOMEM;

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (data == NULL)
		goto out;

	data->cred = rpcauth_lookupcred(NFS_CLIENT(dir)->cl_auth, 0);
	if (IS_ERR(data->cred)) {
		status = PTR_ERR(data->cred);
		goto out_free;
	}

	status = -EBUSY;
	spin_lock(&dentry->d_lock);
	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
		goto out_unlock;
	dentry->d_flags |= DCACHE_NFSFS_RENAMED;
	dentry->d_fsdata = data;
	spin_unlock(&dentry->d_lock);
	return 0;
out_unlock:
	spin_unlock(&dentry->d_lock);
	put_rpccred(data->cred);
out_free:
	kfree(data);
out:
	return status;
}

/**
 * nfs_complete_unlink - Initialize completion of the sillydelete
 * @dentry: dentry to delete
 * @inode: inode
 *
 * Since we're most likely to be called by dentry_iput(), we
 * only use the dentry to find the sillydelete. We then copy the name
 * into the qstr.
 */
void
nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
{
	struct nfs_unlinkdata	*data = NULL;

	spin_lock(&dentry->d_lock);
	if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
		dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
		data = dentry->d_fsdata;
	}
	spin_unlock(&dentry->d_lock);

	if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
		nfs_free_unlinkdata(data);
}